Method and Apparatus for Energy Harvesting Using Rotational Energy Storage and Release

ABSTRACT

An energy harvester is provided for converting an input force into electrical energy and also allowing for energy to be stored and then released at a later time. The energy harvester includes a receiver, energy collector, converter, and holder, and operates in three stages. The receiver receives the input force and the energy collector is moved by the receiver with an input displacement. The energy collector is then held in a catch position. The input force changes direction, and the energy collector is released by the holder and moves with an output displacement that is different from the input displacement. The converter generates electrical energy from the motion created.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application claiming priority toProvisional Application No. 60/879,146 filed Jan. 8, 2007 which isherein incorporated by reference, Provisional Application No. 60/943,380filed Jun. 12, 2007 which is herein incorporated by reference, andProvisional Application No. 60/975,410 filed on Sep. 26, 2007 which isalso herein incorporated by reference.

FIELD OF THE INVENTION

This disclosed invention pertains to energy harvesting mechanisms.

BACKGROUND OF THE INVENTION

The present disclosure generally relates to a device for creatingelectrical energy from mechanical motion.

SUMMARY OF THE INVENTION

The present disclosure involves transforming low frequency excitationinto high frequencies for producing electricity and harvesting energy.An energy collector is deformed with an input displacement, thencaptured, and then released to allow the energy collector to move withan output displacement. The output displacement is either faster or hasa higher frequency, or both, than the input displacement. The energycollector is coupled to a power converter such as a magnetic inductiondevice, piezoelectric material, or an electrorestrictive material tocreate electricity from the motion of the energy collector.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fundamental representation of a energy harvester during aninput stage showing an input force pushing down a receiver;

FIG. 2 is a fundamental representation of the energy harvester from FIG.1 during a hold stage showing a holder capturing the energy collector;

FIG. 3 is a fundamental representation of the energy harvester from FIG.1 during a output stage showing the energy collector released from theholder;

FIG. 4 is a graphical representation showing displacement of the energycollector over time, including an input displacement during the inputstage, a constant displacement during the hold stage, and a outputdisplacement during the output stage, and showing the cycle repeating;

FIG. 5 is a cross-sectional side view of a linear harvester, showing aninput force pushing down a receiver;

FIG. 6 is a cross-sectional side view of the linear harvester from FIG.5, showing the input force pushing down the receiver, storing energy inan energy collector, and engaging a holder;

FIG. 7 is a cross-sectional side view of the linear harvester from FIG.5, showing the input force retreating and pulling up the receiver andshowing the holder released and the energy collector moving with anoutput displacement;

FIG. 8 is a cross-sectional side view of a specific linear harvester,showing the input force pushing down on the receiver and showing thereceiver pushing out on pivot arms of the holder;

FIG. 9 is a cross-sectional side view of the linear harvester from FIG.8, showing the input force pushing down the receiver and storing energyin the energy collector and showing the receiver no longer pushing outon pivot arms of the holder so that the holder can engage;

FIG. 10 is a cross-sectional side view of the linear harvester from FIG.8, showing the input force retreating and pulling up the receiver andshowing the receiver pushing out on pivot arms of the holder, therebyreleasing the holder, and showing the energy collector moving with theoutput displacement;

FIG. 11 is a top view of the linear harvester from FIG. 8;

FIG. 12 is a perspective view of a guide of the linear harvester fromFIG. 8, showing the guide to include input slots and latch slots;

FIG. 13 is a perspective view of the holder of the linear harvester fromFIG. 8 attached to a base and showing the holder to include ladderedopenings;

FIG. 14 is a cross-sectional side view of a rotational harvester,showing an input force pushing down a receiver and deforming an energycollector with an input displacement;

FIG. 15 is a cross-sectional side view of the rotational harvester fromFIG. 14, showing the input force acting in a opposite direction andshowing a holder engaged and locking the energy collector in a catchposition;

FIG. 16 is a cross-sectional side view of the rotational harvester fromFIG. 14, showing the input force acting in an opposite direction andshowing the holder released and the energy collector moving with aoutput displacement;

FIG. 17 is a side view of a specific rotational harvester, showing theinput force pulling up on a crankshaft to rotate an input disc in aninput direction to engage to the receiver and deform the energycollector without showing the coil or generator for illustrativepurposes;

FIG. 18 is a cross-sectional front view of the rotational harvester fromFIG. 17, showing the holder to include a catch and latch and showing thecatch moving over the latch as the receiver moves in the inputdirection;

FIG. 19 is a cross-sectional front view of the rotational harvester fromFIG. 17, showing an input block pushing a receiver block as the inputdisc moves in the input direction;

FIG. 20 is a cross-sectional front view of the rotational harvester fromFIG. 17, showing the input disc moving in a retreat direction and a rampdisengaging the latch from the catch, releasing the holder and allowingthe energy collector to move with the output displacement;

FIG. 21 is a cross-sectional front view of a rotational harvester,showing an input disc deflecting a receiver and moving an energycollector with an input displacement, the input disc can then move awayto allow an energy collector to move with the output displacement.

DETAILED DESCRIPTION OF THE DRAWINGS

An energy harvester 10 is provided for converting an input force 12 intoelectrical energy and also allowing for energy to be stored and thenreleased at a later time. Energy harvesting, also known as energyscavenging, uses displacement or input force 12 to convert some or allof that motion into usable energy.

FIGS. 1-3 show a fundamental embodiment of energy harvester 10. Theenergy harvester 10 is shown to include a receiver 14, an energy storagestructure or energy collector 16, converter 18, and a catch-and-releasemechanism or holder 20. The energy harvester 10 operates in threestages. First is the excitation stage or input stage 22, second is thehold stage 28, and third is the energy conversion or output stage 32.

The input stage 22 is shown in FIG. 1. The receiver 14 receives theinput force 12 and the energy collector 16 is moved by the receiver 14with an input displacement 24.

FIG. 2 shows the second or hold stage 28. The receiver 14 moves away asthe input force 12 changes. The energy collector 16 is held in thelatched or catch position 26 by the holder 20 and has a constantdisplacement 30, as seen in FIG. 4.

FIG. 3 shows the third or output stage 32. Once the receiver 14 hasmoved away and the input force 12 has changed state to a sufficientdistance, the energy collector 16 is unlatched or released by the holder20 and moves with an output displacement 34. The converter 18 generateselectrical energy from the motion created during the output stage 32.

FIG. 4 provides a graphical representation of the energy collector's 16displacement over time during the input stage 22, hold stage 28, andoutput stage 32. During the input stage 22, the energy collector moveswith the input displacement 24 to the catch position 26. In oneembodiment, the rate of displacement during the input displacement 24 isconstant and in another embodiment the rate varies. Next, during thehold stage 28, the energy collector 16 is held in the catch position 26with a constant displacement 30. The duration of the hold stage 28 canvary. In one embodiment, the duration of the hold stage 28 is greaterthan 10 microseconds.

Finally, during the output stage 32, the energy collector 16 oscillatesor vibrates over time, with the output displacement 34. The speed,amplitude, and possibly frequency of the displacement of the energycollector 16 during the output displacement 34 decreases over time. Inone embodiment, the frequency during the output displacement 34 does notdecrease and only the amplitude does. The average speed of the outputdisplacement 34 may or may not be greater than the average speed duringthe input displacement 24. The top speed of the output displacement 34,however, is greater than the input displacement 24. The frequency of theoutput displacement 34 is also greater than the input displacement 24.In another embodiment, the output displacement 34 is damped, and therebyresonates within approximately +/−50% of the undamped frequency or inanother embodiment within approximately +/−25% of the undampedfrequency. The three stages repeat for as long as the input force 12 isapplied.

Input force 12 is any means for displacing the receiver 14 and energycollector 16 during the input stage 22. This input force 12 can involveany motion or force, whether machine, natural, human, or animal. Theinput force 12 can be vibration, waves, walking, pressurized gases orfluids, wind, water flow, walking, running, swinging arms, tidal motion,physiological rhythms (e.g., heart beats), swaying structures, etc.

The input force 12 and motion created can be linear, upward, downward,rotational, vibrational, horizontal, vertical, single direction, mixeddirection, or mixed. The input force 12 and motion created can involvean oscillating linear motion, oscillating rotational motion, continuouslinear motion, or continuous rotation motions. Conventional mechanismscan be used to create any needed motion from the input force 12. Theinput force 12 can be captured by an ocean buoy, tidal machine, strikepad, windmill, water vane, vane, moving water paddle wheel, geothermalpressure source, or other device.

The receiver 14 is any structure receiving the input force 12 anddisplacing the energy collector 16. The receiver 14 can be a linearplunger, rotating wheel, cam, hydraulic piston, lever, pawl, linkage,eccentric wheel, screw, cylinder with an irregular shape, or otherstructure achieving the function described above. The displacement ofthe energy collector 16 can be linear, rotational, angular, or acombination thereof.

The energy collector 16 is any device capable of receiving and storingenergy. In various embodiments, the energy collector 16 can be a linearspring, non-linear spring, constant force spring, laminated spring, leafspring, tension spring, compressible elastic material, elastic cord,torsion spring, flexure springs, a chamber of gas or fluid that iscompressed, other predominantly resilient or nondissipative structure,or a combination thereof.

Design calculations can be used to increase the power output of theenergy collector 16. Adjustments can be made to the spring constant,spring linearity, mass of the moving system, magnet field strength,piezeoelectric material properties, piezoelectric material dimensions,number of turns of an induction coil, load impedance, actuationdisplacement, actuation force, generator characteristics, dampingcoefficients, and system natural and peak frequencies, along with otherdesign parameters.

Energy collector 16 can be made from a wide range of materials. Thesprings 110 and 206, for example, may comprise stainless steel,corrosion resistant steel, heat resistant steel, nickel alloy, cobaltalloy, copper alloy, composite, ceramic, polymer or a combinationthereof.

Energy collectors 16 range in size depending on the application. Forexample, if ocean wave motion is utilized as the input force 12, oneembodiment would require a spring as the energy collector 16 with alength and/or width of between approximately 0.1-100 centimeters or0.001-1 meters. In another example, if a foot strike is utilized as theinput force 12, one embodiment would require a spring as the energycollector 16 with a length and/or width of approximately between 0.01-50millimeters. Embodiments that utilize a foot strike as the input force12 must fit inside the sole of a shoe. In another aspect, the springthickness is between approximately 0.02 millimeters to 1 centimeter.

In other embodiments, the energy collector 16 can comprise gas chambersthat allow gas to be compressed at a low speed and then released tore-expand at a much higher speed. Energy collectors 16, such as gaschambers, can be of variable geometries and therefore tailored todifferent applications.

The input and output profiles 24 and 34 can have a variety of differentspeeds, frequencies, displacements, motions, accelerations,decelerations, etc. In one embodiment, the energy harvester 10 convertsinput force 12 motions with relatively low frequency or low velocity—inthe range of 1 to 10 cycles per second (Hertz). The input displacement24 involves lower frequencies and speeds than the output displacement.Walking and running, for example, occur at 1 to 2 Hertz. Breathing andwave motion occur at less than 1 Hertz. Typical heart rates are slightlymore than 1 Hertz. Vigorous shaking of an object generally occurs atonly a few Hertz.

In one embodiment, the ratio of the average speed of the inputdisplacement 24 to the average speed of the output displacement 34 isgreater than 1:10, 1:20, 1:50, or greater than 1:100. Similarly, theratio of the frequency of the input displacement 24 to the frequency ofthe output displacement 34 is greater than 1:10, 1:20, 1:50, or greaterthan 1:100.

The methods and devices of the energy harvester 10 take advantage ofenergy collectors 16 that, after releasing stored energy, vibrate ormove naturally at a high frequency or velocity, and therefore producemore power than if they were to only move at the frequency or velocityof the displacement used to deflect them. For example, the springs ofthe various spring/magnet embodiments described in this application arereleased quickly and may vibrate at 10 to 100 Hertz or greater, eventhough the forced deflection of the springs is only 1 or 2 Hertz. Thehigh ratio of output to input permits the use of smaller and morelightweight components, e.g., smaller springs, magnets and coils.

The converter 18 is a magnetic induction device (e.g., generator ormotor), piezoelectric material, or an electrorestrictive material.Magnets used in the converter 18 can comprise neodymium iron boron,samarium cobalt, alnico, ceramic or ferrite or combinations thereof. Themagnets can be round bars, rectangular bars, horseshoes, rings ordonuts, discs, rectangles, multi-fingered rings, and other custom shapesand have a wide range of sizes. In one embodiment, the present inventionutilizes a foot strike as an input force 12 and the magnet used isbetween approximate 1 millimeter to 2 centimeters in length and width.

The wire coil of the converter 18 can be formed of insulated coppermagnet wire with a wire gauge of between approximately 15 and 50. One ofordinary skill in the art knows how to optimize the wire coil and magnetfor the desired application by selecting an appropriate wire gauge andcoil geometry. The converter's 18 wire coil can be in a proximitylocation relative to the magnet so that the produced voltage ismaximized. In one embodiment, the dimensions of the coil areapproximately 2 centimeters long, with approximately 1 centimeter insidediameter and 1.5 centimeters outside diameter.

In another embodiment, converter 18 can be a generator or electric motorused as a generator. The motor can be driven by coupling it to themotion of the energy collector 16. This motion produces electric powerin the generator or motor which can then used directly or stored withinan energy storage component such as a battery or capacitor. Possiblegenerators or motors include but are not limited to brushless DC and ACmotors, linear induction, and DC and AC motors with brushes.

The holder 20 is any device that catches and releases the energycollector 16 at the proper time. The holder 20 can be a catch andrelease mechanism or other device that captures the energy collector 16and then allows the energy collector 16 to be released after thereceiver 14 and input force 12 have moved a sufficient distance orceased storing more energy in the energy collector 16.

The present disclosure provides for two embodiments of energy harvester10. The first embodiment or linear harvester 100 is for an energycollector 16 that is based on linear movements and is seen in FIGS.5-13. The second embodiment or rotational harvester 200 is for an energycollector 16 that is based on rotational movements and is seen in FIGS.14-21. In both embodiments the energy collector 16 is displaced at aninput displacement 24 during the input stage 22, is then held in thecatch position 26 during the hold stage 28, and then released and moveswith an output displacement 34 during the output stage 32, as shown inFIGS. 1-4.

The linear harvester 100 is shown in a basic form in FIGS. 5-7 and isshown in a specific embodiment in FIGS. 8-13. One of ordinary skill inthe art can appreciate that many other embodiments are possible inaccordance with the present disclosure. The receiver 14 of the linearharvester 100 includes a guide 102, a base 104, an input arm 106, and aninput plunger 108. The guide 102 is connected to the base 104. The guide102 is a cylindrical structure or other shaped structure within whichthe receiver 14 travels and that houses the energy collector 16.

The input arm 106 extends inside the guide 102. One end of the input arm106 interacts with the input force 12 and the other end is coupled tothe input plunger 108. The connection between the input arm 106 andinput plunger 108 can be a rigid or pivotal connection. The pivotalconnection can be used to account for different force vectors containedin the input force 12.

The linear harvester's 100 energy collector 16 comprises a linear spring110. The converter 18 is shown to include a magnet 112, coil 114,circuit 116, and an electrical energy storage device 117. The magnet 112is attached to the top of the energy collector 16. The coil 114 issupported by the base 104 and is positioned around the magnet 112 andthe circuit 116 is electronically connected to the coil 114, which isconnected to the electrical energy storage device 117. The electricalenergy storage device 117 can include power conditioning electronics andcan include a capacitor, battery, or other device capable of receiving,storing, and releasing electric energy.

The linear harvester's 100 holder 20 includes catches 118 and latches120. The catches 118 are connected to or formed within the coil 114 orother structure surrounding the guides 102. The latches 120 are attachedto the top surface of the magnet 112 and extend beyond the edge of themagnet 112, beyond the guide 102, to interact with the catches 118. Inother embodiments the latches 120 are attached to the bottom of themagnet 112, another portion of the magnet 112, the linear spring 110, orany other structure attached thereto.

Various embodiments of the holder 20 are possible that temporarily holdthe energy collector 16 for a set period of time or movement of receiver14 or input force 12. In one embodiment, the holder 20 responds to theposition or direction of motion of the input arm 106 or input plunger108. The distance between the catches 118 and the latches 120 can bevaried to maximize the energy stored in the linear spring 110.

In another embodiment, the holder 20 components are electronicallycontrolled, receiving input from sensors measuring the position andstrength of input force 12, to maximize efficiency. The catches 118 orlatches 120 can also include a retraction mechanism. The retractionmechanism can be a spring biased device or other conventional device toretract the catch 118 or latch 120 when the input force 12 is applied.

During the input stage 22, as seen in FIG. 5, the input force 12 pushesdownward on the input arm 106 and plunger 108. The plunger pushes downon the latch 120, magnet 112, and linear spring 110. The energycollector 16 and magnet 112 move with the input displacement 24 seen inFIG. 4. As seen in FIG. 6, the input force continues to push until thelatch 120 is underneath the catch 118.

Next, is the hold stage 28. The input force 12 changes states orreverses direction. Meanwhile, the energy collector 16 and magnet 112are held in the catch position 26 with a constant displacement 30, asseen in FIG. 6. Accordingly, linear spring 110 is held compressed andstores energy.

Once the receiver 14 has moved sufficiently away, the output stage 32begins. The latches 118 are released from the catches 120 and the linearspring 110 is accordingly released, as seen in FIG. 7. The linear spring110 moves and vibrates with the output displacement 34 as seen in FIG.4. The magnet 112 moves with the linear spring 110 and electricity isproduced in the coils 114 through magnetic induction. The circuit 116delivers the electricity to power conditioning electronics included inthe electric energy storage device 117 or to an electricity-consumingdevice or power grid.

FIGS. 8-13 show a specific embodiment of the linear harvester 100. Theholder 20 is shown to include pivot arms 122 attached to the base 104 bypivots 124. Ramps 126 are attached at the top of the pivot arms 122extending to the inside. The input plunger 108 includes tongues 128 oneither side. As seen in FIG. 12, the guide 102 includes tongue slots 130and latch slots 132. Tongues 128 extend into and travel within tongueslot 130. Latches 120 extend into and travel within a lower portion oftongue slots 130 and latch slots 132 located beneath the tongue slots130.

The catches 118 comprise laddered openings 134 vertically arrangedtowards the bottom position of the pivot arms 122, as seen in FIG. 13.The pivot arms 122 are biased in an upright direction by torsion springs136 in the pivots 124. The pivot arms 122 can also be biased by springsconnected to the guide 102 or by another conventional means. In anotherembodiment, the pivot arms 122 are themselves elastic. Structures canalso be added to the pivot arms 122 for added support.

During the input stage 22, latch 120 enters ladder openings 134 as thereceiver 14 is moved downward. These multiple ladder openings 134account for different distances of travel by the receiver 14 whilemaximizing the amount of energy stored. During the hold stage, tongues128 make contact with the ramps 126, causing the pivot arms 122 to pivotoutward. When the pivot arms 122 pivot outward, the ladder openings 134are moved away from the latches 120 and the linear spring 110 isaccordingly released and vibrates, as seen in FIG. 10.

The rotational harvester 200 receives a rotational movement and is shownin a basic form in FIGS. 14-16 and is shown in a specific embodiment inFIGS. 17-20. One of ordinary skill in the art can appreciate that manyother embodiments are possible in accordance with the presentdisclosure. The receiver 14 of the rotational harvester 200 includes anextension 202 and a base 204. The rotational harvester's 200 energycollector 16 comprises a torsion spring 206. One end of the torsionspring 206 is connected to the base 204 and the other end is connectedto the extension 202.

The converter 18 of the rotational harvester 200 is shown to include amagnet 208, coils 210, circuit 212, and an electrical energy storagedevice 214. The magnet 208 is suspended in the interior of the torsionspring 206. In another embodiment the magnet 208 is formed around theexterior surface of the torsion spring 206. The coils 210 are locatedaround the exterior of the torsion spring 206 and are electronicallyconnected. The circuit 212 is electronically connected to the coils 210,which is connected to the electrical energy storage device 214. Theelectrical energy storage device 214 can include power conditioningelectronics and can include a capacitor, battery, or other devicecapable of receiving, storing, and releasing electric energy.

The rotational harvester's 200 holder 20 includes a latch 216 and catch218. The latch 216 is connected, or formed as part of, the base 204. Thecatch 218 is connected to the extension 202.

During the input stage 22, as seen in FIG. 14, the input force 12 pushesdownward on the extension 202 and latch 216 winds the torsion spring206. The energy collector 16 and magnet 208 moves with the inputdisplacement 24 seen in FIG. 4. The input force 12 continues to pushuntil the catch 218 is underneath the latch 216.

Next, is the hold stage 28. The input force 12 reverses direction, asseen in FIG. 15. The receiver 14, energy collector 16, and magnet 208are held in the catch position 28 and have a constant displacement, asgraphically shown in FIG. 4. Accordingly, torsion spring 206 is held ina wound position and stores energy.

Once the input force 12 changes direction or has caused the receiver tomove a sufficient distance, the output stage 32 begins. The catch 218 isreleased from the latch 216 and the torsion spring 206 is accordinglyreleased, as seen in FIG. 16. The torsion spring 206 is displaced andvibrates with the output displacement 34, as graphically shown in FIG.4. The magnet 208 moves with the torsion spring 206 and electricity isproduced in the coils 210 through magnetic induction. The circuit 212delivers the electricity to the electrical energy storage device 214 orto an electricity-consuming device or power grid.

FIGS. 17-20 show a specific embodiment of the rotational harvester 200.The receiver 14 is shown to include an input disc 220 to createrotational movement from input force 12 through a crankshaft 222. Theextension 202 is also shown to be formed in the shape of a disc. Theinput disc 220 has an input block 224 configured to interact with anextension block 226 on the extension 202.

Ramp 228 is located on the inside of the input disc 220 to interact witha ramp lobe 230 of latch 216 which is connected to the base 204. Thecatch 218 is comprised of laddered teeth 232 located along the outerperiphery and on the inside of extension 202. The latch 216 is biased sothat the engagement lobe 234 of latch 216 interacts with laddered teeth232. The biasing of latch 216 can be achieved in a number of ways. Inone embodiment the biasing is achieved by weight distribution and inanother embodiment by a spring.

During the input stage 22, the input disc 220 is rotated in inputdirection 236. Extension lobe 234 of latch 216 moves over the ladderedteeth 232 as the input disc 220 rotates, allowing the extension 202 torotate with the input disk 220 but to not counter rotate, as seen inFIGS. 18 and 19. The input block 224 then pushes extension block 226 tomove torsion spring 206 in a radial direction with the inputdisplacement 24, storing energy. The multiple laddered teeth 232 accountfor different distances of radial travel by the receiver 14 whilemaximizing the amount of energy stored.

During the hold stage, the input disc 220 changes direction and moves inthe retreat direction 238. The torsion spring 206 is now held in thecatch position 26. After the input disc 220 has moved a sufficient,predetermined, distance such that the input block 224 will not interferewith the extension block 226, the ramp 228 makes contact with the ramplobe 230 of the latch 216, causing the latch 216 to pivot. The extensionlobe 234 accordingly moves downward and no longer interacts with catch218 as seen in FIG. 20. The torsion spring 206 is accordingly releasedand vibrates with the output displacement 34, as seen in FIG. 20 andgraphically shown in FIG. 4.

In another embodiment, not illustrated, the rotational harvester 200does not utilize a torsion spring 206. The rotational movement isconverted to a linear motion by a screw, cam, or other conventionalmechanism and deforms a linear spring or other energy collector 16.

In other embodiments, the constant displacement 30 is not involved. Forexample, a change in direction of input force 12 may trigger the releaseof holder 20, as seen in FIG. 21. The input force 12 drives crankshaft222 and input disc 220 such that input disc 220 continuously rotates inthe same rotation direction 240. Extending from the input wheel is catch216. As the input disc 220 rotates so that catch 216 makes contact withand moves extension 202 and energy is imparted in the torsion spring206. At some point in the motion of the catch 216, it displaces out ofcontact with extension 202, and the torsion spring 206 and a magnet 208vibrate with the output displacement 34. This embodiment can also beadapted to the linear harvester 100 whereby the catch 216 makes contactwith and pushes down directly on magnet 112. Multiple energy harvesterscan also be placed around the input disc 220 such that a single catch216 makes contact with multiple extensions 202 during each rotation.

Various embodiments of the present disclosure can be used in arrays, orin conjunction with one another, to increase the overall power output.For example, multiple spring and magnet systems or multiple energystorage and power generation components can be set up in an array.

Energy harvester 10 can be used to power a wide range of applications,for example, powering remote transmitting stations, powering remotemonitoring stations, powering autonomous vehicles, providing commercialpower, providing power on board mobile vehicles, providing off gridpower, powering consumer electronics, etc.

The energy harvester 10 can also be used to power MicroelectromechanicalSystems (MEMS) or Nanoelectromechanical Systems (NEMS) or other machinesand devices that are very small. In these MEMS and NEMS applications,the size of the energy harvester 10 and its components are, in oneexample, between 10 nanometers to 500 microns. The size of the energyharvester 10 is adjusted to meet the needs of the application and is notlimited.

While embodiments have been illustrated and described in the drawingsand foregoing description, such illustrations and descriptions areconsidered to be exemplary and not restrictive in character, it beingunderstood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected. The descriptionand figures are intended as illustrations of embodiments of thedisclosure, and are not intended to be construed as containing orimplying limitation of the disclosure to those embodiments. There are aplurality of advantages of the present disclosure arising from variousfeatures set forth in the description. It will be noted that alternativeembodiments of the disclosure may not include all of the featuresdescribed yet still benefit from at least some of the advantages of suchfeatures. Those of ordinary skill in the art may readily devise theirown implementations of the disclosure and associated methods, withoutundue experimentation, that incorporate one or more of the features ofthe disclosure and fall within the spirit and scope of the presentdisclosure.

1. An energy harvester comprising: an energy collector secured to abase, a receiver for receiving an input force and deforming the energycollector to a catch position according to an input displacement whereinthe receiver travels with a rotational motion, a holder for temporarilyholding the energy collector in the catch position with a constantdisplacement and releasing the energy collector from the catch position,so that the energy collector moves with an output displacement differentfrom the input displacement, and a converter for transforming therotational motion of the energy collector into electric energy.
 2. Theenergy harvester of claim 1, wherein the output displacement has ahigher frequency than a frequency of the input displacement.
 3. Theenergy harvester of claim 2, wherein a ratio of the frequency of theinput displacement to the frequency of the output displacement isgreater than approximately 1:10.
 4. The energy harvester of claim 1,wherein the output displacement has a higher top speed than a top speedof the input displacement.
 5. The energy harvester of claim 4, whereinthe top speed of the input displacement to the top speed of the outputdisplacement is greater than approximately 1:10.
 6. The energy harvesterof claim 1, wherein the energy collector includes a torsion spring. 7.The energy harvester of claim 1, wherein the receiver moves away fromthe energy collector while the holder is holding the energy collector.8. The energy harvester of claim 1, wherein the receiver travels with arotational motion.
 9. The energy harvester of claim 1, wherein thereceiver includes an input disc.
 10. The energy harvester of claim 1,wherein the converter uses magnetic induction.
 11. The energy harvesterof claim 10, wherein the converter includes a magnet attached to theenergy collector.
 12. The energy harvester of claim 11, wherein theconverter includes a coil.
 13. The energy harvester of claim 1, whereinthe converter includes a piezoelectric material.
 14. The energyharvester of claim 1, wherein the receiver and input force do not impedethe output displacement of the energy collector.
 15. A method forharvesting energy comprising: deforming an energy collector by an inputforce and a rotational motion at an input displacement, capturing theenergy collector for a period of time at a constant displacement,releasing the energy collector at an output displacement, and convertingthe rotational motion of the energy collector into electric energy. 16.A method for harvesting energy comprising: an input stage during which aenergy collector is deformed by an input force and a rotational motion,a hold stage during which the energy collector is held and the inputforce changes direction, and an output stage during which the energycollector is released and a output displacement of the energy collectoris converted to electricity.